People possess different learning styles when it comes to learning exercises. Some are adept at putting verbal instructions into proper use. Others are visual learners and are good at mimicking what is demonstrated to them. Still others require manual cuing in order to learn how to perform certain movements.
The above learning styles are auditory, visual and tactile, respectively.
One particular area of motor learning where I find that folks require tactile cuing is scapular mobility and stability training.
What are the scapulae? They are the shoulder blades that articulate with the back of your thorax (rib cage). I like to describe the scapulothoracic joint as the "core" of the shoulder. In a healthy shoulder, it ought to be able to move in multiple planes and directions. It also needs to be stable through it's given ranges. Training the movements of the scapulothoracic joint is an integral part of shoulder rehabilitation. What I find with most folks though is that they have a very difficult time learning how to isolate and control these movements.
Here is a quick video in which I demonstrate how to use a common rehabilitative device, a foam roller, to help manually cue one of the important movements of the scapula, which is retraction.
Give this a try yourself, or if you're a rehabilitation specialist, use it with your client who has a difficult time with this movement. I have found it to be a very helpful first step towards improving scapular movement and control.